The objective of this project is to try different steering mechanisms.
The bike was designed as an experimental rig that could be easily modified as bugs/failures became evident.
Photo 1 shows straight ahead neutral turning tendencies. (rideable)
Photo 2 turning about axis A B self centering. Note that tie rod is in the center of the constraining ring. (rideable)
Photo 3 turning & leaning, See that the tie rod moves sidewards. (unrideable, considerable effort required to straighten up)
The lift generated by a turn is unfortunately overwhelmed by the drop caused by the swing action of the tie rod when the bike is leant. Making this prototype unrideable.
A RETHINK on joint C. see Photo
Starting of from the roadside kerb. see Video (614 KB)
Handling a demo ride. see Video (3208 KB)
By moving joint C to its new position, we now have steering around A C or "mid bike steering" with a self aligning setup which is rideable both in turning, or leaning, or both. This is a consequence of the tie rod C B swinging out about C, thus shortening the wheelbase sufficiently to lift the rider creating a self centering force.
Conventional trail geometry only seems necessary for initial slow speed starts up to 6kmh approximately.
The bike was ridden around a local velodrome and was unaffected by the steep camber unlike some other lean steer bikes.
GREAT you may think but another thing now influences steering. It's the same thing that Penny Farthing riders face which is the off-set forces created when pedalling. A wobbling from side to side with each pedal rotation.
Turns and stability improve with speed as wobble diminishes above 6kmh. The faster you go the more it feels and handles like an ordinary bicycle. However alighting and manoeuvres below 6kmh require some mental attention. Starting off seated with one foot on a kerb, with a slight push off, seems to be the best approach.
The project has been an enlightening, an alternate view of the conventional bicycle steering geometry theory.
Challenge experimenters. A rethink to lessen "pedal wobble" GO figure it out. Post note results to Ross Harrop.
